A seat belt functions to restrain a passenger's body in a seat by inhibiting excessive speed of webbing withdrawal when a vehicle is engaged in cornering, rapid acceleration or deceleration.
In general, a seat belt retractor comprises a retraction spring that actuates the rotation power of a spool for retraction and protraction of webbing. The seat belt retractor further comprises a frame that is secured on the vehicle to support the load and weight imposed on the webbing. The seat belt retractor further comprises a locking pulley that prevents the rotation of the spool in the direction of the webbing being withdrawn. The seat belt retractor further comprises a sensor that detects rapid protraction of the webbing. The seat belt retractor further comprises a sensor that detects the vehicle's stability and rapid acceleration/deceleration. Particularly, the stability sensor may be be fitted in balance aligned with the vehicle.
At present, various mechanisms and systems are employed for each particular vehicle model. Such requires additional design and design time to maintain each vehicle's stability and sensors as the installation angle of the stability sensor for each make is slightly different. The arbor that transmits the rotation force to the spool by fastening the retraction spring tends to become separated during spring winding, and also noisy during protraction and retraction of the webbing. Operational failure of the webbing during or after manufacturing causes problems associated with complicated assembly processes.